1. Field of the Invention
This invention relates to a zoom lens having a large zoom ratio, which zoom ratio is 6 and F number is approximately 1.4, and having a large aperture, the zoom lens being compact, and particularly to a zoom lens suitable for a color video camera.
2. Description of the Prior Art
Generally, it has a tendency that a camera lens having a large aperture is demanded and the lens which is short in overall length of a lens and small in diameter is desired to provide compactness. Particularly, a lens for a video camera, in which an imaging element has a low sensitivity, is desired to have a large aperture.
However, when the lens is designed to have a large aperture, compensation of aberration is difficult to make, and therefore, in many cases, the refracting power of each unit of the zoom lens is made weak and the overall length of the lens is lenghtened. Conversely, even if the overall length of the lens should be shortened, a large aperture cannot be maintained over the whole zoom area or even if the large aperture can be maintained, a diameter of a front lens is apt to increase.